Season 4, episode 10 "Ben 10 vs. The Negative 10, Part 2": When the Forever King makes his announcement "Nothing will stop this little home-coming", he stands outside the Mount Rushmore base on bare soil. But in the scene where Max reviews the recording of this speech, all of a sudden we find the Forever King standing on a neatly tiled floor.

About all of the aliens found in attendance of Kevin's mega cruiser strangely resemble those individuals previously seen (on the selfsame ship) in episode 2-5, "Grudge Match", whereas they should have escaped the cruiser near the end of that episode.